Management of Non-Small Cell Lung in Cancer Patients with Stable Disease

Disease stabilization after first-line chemotherapy, also known as induction chemotherapy, is defined, according to the Response Evaluation Criteria in Solid Tumours (RECIST), as having neither sufficient shrinkage to qualify as a partial response (PR) nor sufficient increase to qualify as progressive disease (PD). In oncology, stable disease (SD) has often been viewed as an equivocal result and is therefore of unclear clinical value. In SD patients with advanced non-small cell lung cancer (NSCLC) who have already received four cycles of first-line chemotherapy with platinum agents plus a third-generation agent (gemcitabine, vinorelbine, docetaxel or paclitaxel) or pemetrexed, the continuation of the original treatment is not recommended according to the American Society of Clinical Oncology (ASCO) guidelines. The ASCO guidelines recommend maintenance with bevacizumab or cetuximab, as tolerated until progression, only for platinum-based chemotherapy combined with bevacizumab or cetuximab. Several trials and a meta-analysis have, however, suggested a role for maintenance treatment in patients without progression after induction chemotherapy. The National Comprehensive Cancer Network guidelines recently suggested that maintenance therapy may be considered after four to six cycles of induction platinum doublets for patients with tumour responses or SD, and recommended first-line treatment with epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors in EGFR mutated patients to continue until PD. More recently, two randomized clinical trials that compared pemetrexed or erlotinib with a placebo demonstrated a better overall survival in favour of maintenance therapy. In subgroup analyses for both trials, patients with SD after first-line induction chemotherapy had pronounced survival benefits when erlotinib or pemetrexed maintenance therapy was given, although this result was not achieved in patients with a complete response or PR after induction chemotherapy. The management of patients with SD after first-line chemotherapy is an important issue because only a minority of patients with advanced NSCLC experience tumour shrinkage after standard platinum-based chemotherapy. Many more patients experience either SD or PD. The notion that the prognosis of SD patients varies greatly due to the complexity of SD should, however, be taken into careful consideration for the treatment decision. Therefore, suggestions for the further classification of SD are urgently needed to enable the use of an alternative therapy at an early time.